Faculty Publications
Reply to Eells et al. (Daily Cranberry Prophylaxis to Prevent Recurrent Urinary Tract Infections May Be Beneficial in Some Populations of Women)
Document Type
Article
Journal/Book/Conference Title
Clinical Infectious Diseases
Volume
52
Issue
11
First Page
1394
Last Page
1395
Abstract
TO THE EDITOR—We appreciate the kind words of Eells et al [1] regarding our recent article describing results of a randomized, double-blind clinical trial of the effects of cranberry juice versus placebo juice in preventing urinary tract infection (UTI) among 319 otherwise healthy women [2]. We were puzzled, however, with their statements regarding the study power. Power is a function of the effect size, sample size, and variance. Given that we observed a greater number of UTIs among participants receiving cranberry juice, it would have required a substantially larger sample size than that suggested by Eells et al [1], to overcome the observed deficit and produce a positive result—even if the study had been designed for a 14% recurrence rate. Thus, it does not seem to us conservative to assume—as their letter implies—that had our trial been doubled in size we may have observed a beneficial effect of cranberry juice over placebo. We note also, that the published trials among similar populations [3, 4] had sample sizes that were less than half of that of our trial.
Department
Department of Biology
Original Publication Date
6-1-2011
DOI of published version
10.1093/cid/cir194
Recommended Citation
Wen, Ai; Foxman, Betsy; Elgersma, Kenneth; Buxton, Miatta; Zhang, Lixin; and Barbosa-Cesnik, Cibele, "Reply to Eells et al. (Daily Cranberry Prophylaxis to Prevent Recurrent Urinary Tract Infections May Be Beneficial in Some Populations of Women)" (2011). Faculty Publications. 6044.
https://scholarworks.uni.edu/facpub/6044
